1. Field of the Invention
The present invention relates to a lens-fitted photo film unit. More particularly, the present invention relates to a lens-fitted photo film unit in which an electronic flash unit is incorporated and of which a size is reduced.
2. Description Related to the Prior Art
A lens-fitted photo film unit is a simplest type of single-use camera preloaded with unexposed photo film. The lens-fitted photo film unit includes a main body, front cover and rear cover. The main body accommodates the photo film.
The front and rear covers cover the front and rear of the main body. There is an exposure unit secured to the center of the main body, and includes a mechanism for taking an exposure. A cassette holder chamber is formed in an end of the main body to contain a cassette shell of a photo film cassette. A roll holder chamber is formed in a remaining end of the main body to contain a roll of the photo film drawn from the cassette shell and wound in a roll form.
The lens-fitted photo film unit has various characteristics in a small size, simple structure and low cost. Among various types of the lens-fitted photo film unit, one includes an electronic flash unit. The flash unit is constituted by a printed circuit board, flash emitter, main capacitor and battery. The flash emitter includes a flash discharge tube. The battery supplies the printed circuit board with power. To obtain sufficiently high amount of flash light, the main capacitor has a relatively high capacitance, typically in consideration with photographic fields short of ambient light, for example scenes at night or indoor scenes.
Among the elements included in the flash unit, the main capacitor and battery have relatively great volumes to take large space. Capacitance of the main capacitor is correlated with the size of the main capacitor. The considerable sizes of the main capacitor and battery are inconsistent to an idea of reducing the size of the lens-fitted photo film unit.
To secure the flash unit to the lens-fitted photo film unit, the printed circuit board is disposed on a side of the exposure unit. The main capacitor is oriented to extend horizontally on an upper side of the roll holder chamber. The battery is oriented to extend horizontally under the exposure unit and printed circuit board. A distance between outer surfaces of the cassette holder chamber and roll holder chamber is predetermined equal to or more than a horizontal size of the battery to keep the battery contained between the cassette holder chamber and roll holder chamber.
This disposition can avoid an increase in the vertical size and thickness of the lens-fitted photo film unit. However, there occurs an increase in a size of the lens-fitted photo film unit in the horizontal direction or photo film advancing direction.
In view of the foregoing problems, an object of the present invention is to provide a lens-fitted photo film unit of which a horizontal size is reduced in a photo film advancing direction.
In order to achieve the above and other objects and advantages of this invention, a lens-fitted photo film unit preloaded with unexposed photo film includes a main body, having a cassette holder chamber and a roll holder chamber, the cassette holder chamber containing a cassette shell, the roll holder chamber containing a roll of the photo film drawn from the cassette shell. An exposure unit is secured to the main body between the cassette holder chamber and the roll holder chamber, for providing an exposure in the photo film. An electronic flash unit is secured to the main body, for illuminating a photographic field to be photographed. A battery supplies the flash unit with power, the battery being disposed under the exposure unit, and having at least one portion disposed under the roll holder chamber.
In a preferred embodiment, a lower edge of the roll holder chamber is disposed higher than a lower edge of the cassette holder chamber, and the battery extends horizontally in a lengthwise direction thereof.
The cassette holder chamber has a first outer wall, the roll holder chamber has a second outer wall, and a distance between the first and second outer walls is shorter than a size of the battery in a horizontal direction.
The battery has a cylindrical shape, and has a diameter smaller than a diameter of a UM-3 battery.
The battery is a UM-4 type.
The flash unit includes a flash emitter for applying flash light to the photographic field. A main capacitor stores charge for flash emitting operation of the flash emitter, the main capacitor being disposed above the roll holder chamber, and having capacitance of 15-50 xcexcF.
The photo film has photo film speed of ISO 1600 or higher.
The roll holder chamber includes a lower wall for supporting the roll of the photo film. A lower opening is formed in substantially a middle of the lower wall. Furthermore, a lower lid closes the lower opening. A skirt projection portion is formed with a periphery of the lower opening to project downwards, disposed inside a periphery of the lower wall, and fitted on the lower lid. The battery is disposed at least partially under the lower wall and outside the skirt projection portion.
According to another aspect of the invention, a lens-fitted photo film unit preloaded with unexposed photo film includes a main body, having a cassette holder chamber and a roll holder chamber, the cassette holder chamber containing a cassette shell, the roll holder chamber containing a roll of the photo film drawn from the cassette shell. An exposure unit is secured to the main body between the cassette holder chamber and the roll holder chamber, for providing an exposure in the photo film. An electronic flash unit is secured to the main body, for illuminating a photographic field to be photographed. A battery is disposed under the exposure unit, for supplying the flash unit with power, the battery having a size equal to or less than substantially ⅔ of a size of a UM-3 battery in a lengthwise direction thereof.
In a preferred embodiment, the flash unit includes a flash emitter for applying flash light to the photographic field. A main capacitor stores charge for flash emitting operation of the flash emitter, the main capacitor being disposed above the roll holder chamber, and having capacitance of 15-50 xcexcF. The battery has a cylindrical shape, has a diameter substantially equal to a diameter of a UM-3 battery, and is disposed to extend between the cassette holder chamber and the roll holder chamber.
The size of the battery is equal to or more than substantially xc2xd of the size of the UM-3 battery in the lengthwise direction thereof.
The photo film has photo film speed of ISO 1600 or higher.